Global warming, also known as anthropogenic (or human-caused) global warming, is the rising average temperature of Earth's atmosphere and oceans and its related effects. Global warming denialism refers to fossil fuel industry-funded claims that global warming:

It should not be confused with those that accept that anthropogenic global warming is a major threat, but dispute whether or not the government regulations put in place to combat it result in a desirable outcome.

The phrase “global warming” by itself is often used to refer to the rapid rise in temperatures that the Earth has experienced since the start of the Industrial Revolution. In the last 100 years, Earth's average surface temperature increased by about 0.8 °C (1.4 °F) with about two thirds of the increase occurring over just the last three decades. As a result, anthropogenic global warming has recently become a major concern for humanity. Such concerns are supported worldwide by the wide majority of climatologists.

Global warming is an increase in temperature in addition to the natural greenhouse effect. The greenhouse effect interacts with other planet-wide influences such as the Milankovitch cycles in order to produce long-term climate movements. Many gases contribute to the greenhouse effect, some of the most important being water vapor, methane and carbon dioxide. Black carbon (i.e. soot) is third only to carbon dioxide and methane for its contribution to global warming, but it is the most effective at raising temperatures in the Arctic by reducing the albedo.[3]

In its simplest form, the argument for anthropogenic climate change goes as follows.

The Earth's atmosphere keeps the planet much warmer than it would be without an atmosphere.[4]

The main gases which contribute to this are carbon dioxide (CO2), methane and water vapor.[5] Collectively these are called greenhouse gases (GHGs).

The ability of these gases to act as greenhouse gases can be shown in a laboratory.[6]

The quantity of these greenhouse gases in the atmosphere has increased sharply since the Industrial Revolution, and their concentration continues to do so.[7]

The concentration of these gases has increased as a consequence of human activity.[8]

The temperature of Earth's atmosphere has been increasing and continues to increase.[9]

The increase in global temperature correlates with the increases of greenhouse gases.[10][11]

Up to this point virtually all scientists are in agreement — including those few global warming "skeptics" who understand the science and the data.[12] Consequently the skeptics need to somehow attack the final leg of the argument:

8. The increase in temperature has been caused by the increase in greenhouse gases.[13][14]

The logical consequence of this conclusion is that we should reduce the quantity of greenhouse gases which we pump into the atmosphere so as to reduce global warming.

Note that the statement that The increase in global temperature correlates with the increases of greenhouse gases is only true on a very broad timescale: GHGs have increased roughly exponentially but the temperature signal is far noisier, and displays almost no correlation with GHG changes on an annual basis, as expected. This is due to a variety of factors, from intrinsic noise in the climate system to the existence of other important forcing factors (most notably sulphate aerosols and global dimming, which are cooling factors).

Also note that while water vapour is correctly listed as a GHG, the human emissions of water vapor are not important in forcing climate change; water vapour is best thought of as a response to temperature change rather than a cause, because its atmospheric lifetime is very short (about 10 days), unlike other gases such as CO2.[15]

While projections of the potential (maximum) temperature rise resulting from a doubling of CO2 have ranged from 2°C to 6°C, there's broad agreement that anything above 2°C will mean we are beyond recovery. The International Energy Agency suggests that the window to prevent this from occurring will close by 2020,[16] a view shared by the OECD.[17] So let's get cracking.

CO2 emissions have been stabilizing but methane emissions have risen dramatically during the past ten years for unknown reasons. This undermines efforts to combat global warming and there is a risk of an uncontrollable run away greenhouse effect.[18]

Various components of climate change. The error bars, particularly on the negative components, are currently the focus of much climate research in order to improve predictive climate models. Denialists, who can't or don't want to understand graphs, probably won't understand this graph.

A scientific consensus is reached when the vast majority of the scientists involved in a discipline broadly agree on the interpretation of the evidence pertaining to a specific scientific question. When this occurs the case can be considered to have been demonstrated and the burden of proof then falls on those who would dispute the consensus. The following national and international organizations are part of the consensus that global warming is a real phenomenon for which humans are responsible:

Though some have taken non-committal stances, the vast majority of scientific bodies are convinced by the evidence.[19] In addition, those pinko tree-huggers at the Pentagon now rank global warming as a "destabilizing force" (damn enviro-weenies).[20][21]

Despite the clarity of the facts, behavioral/social science tells us that simply shoving global warming related scientific data into their face simply solidifies their existing beliefs.[22] There's even a college offering free online classes that teaches you both the science of what is going on and how to fight denialism properly.[23]

National or international scientific bodies that reject anthropogenic global warming[edit]

Greenhouse gas emissions per unit of energy produced, for different types of power plants.

Anyone who, even after the occurrence of extreme weather events that seem to intensify yearly, does not see the validity of decades of scientific documentation that catalogues the existence of global warming, is a lost cause. Simply put, time is of the essence. Instead of spending resources trying to convince people (anyone who still doesn't get it, will never get it) that global warming is in fact real, the people in this world who have a clue should put the focus on action and moving forward by championing the solutions to this crisis that threatens the entire planet. These solutions involve fostering the use of hybrid/electric vehicles, and replacing fossil fuels with wind power, solar power, nuclear power, and perhaps[24] hydro power. (Fun fact: Solar power's contribution to global warming is 2-4 times worse than nuclear, per kWh.)[25][26]

One form of Enhanced Oil Recovery consists in injecting CO2 into reservoirs in order to extract more oil. Ongoing experiments aim at obtaining the CO2 from clean coal plants equipped with carbon capture technology.[27]. Although the technology itself seems to work[28][29], it is not clear how sequestering coal CO2 to help produce more oil will affect atmospheric CO2.

Air capture technology to collect CO2 is routinely used in spacecraft and submarines. However, it requires energy to operate and a 2011 study estimated that processing the whole atmosphere would not be cost-effective. One of the authors noted that planting vegetation is more feasible but would require a significant amount of land.[30] However, this shouldn't discourage efforts to help reduce the effects of emissions, and in theory could act as a supplement to other methods of CO2 scrubbing. One good example of plants that consume plenty of CO2 are pine trees used in farming. Though they tend to use the nutrients in the ground, in theory they can be replenished from biosolids (refined animal feces). [31] A problem with plants is what to do with all the dead plant matter. Decomposing plants release CH4, an even worse greenhouse gas than CO2 and there is simply not enough storage on earth for all the wood forests of the needed magnitude would produce. However, we could bury the resulting biomass underground, in effect recreating the origin of the fossil fuels that got us into this mess in the first place.

Climate change is expected to affect farming practices by requiring a shift in corn planting windows. In order to address this, Illinois scientists have suggested various cropping strategies for flexible risk management: planting early so that droughts don't affect harvests, or creating cropping systems that can keep the soil moist through droughts to complement drought-resistant cultivars.[32]

In the event that such things are a dead end (and there is the opinion that it's too late to reverse climate change by merely reducing or stopping what we're doing) there is geo-engineering. Yes people, chemtrails!

This involves trying to force climate change back in the opposite direction intentionally, or with what has been described as terraforming Earth. Among these options is lacing the atmosphere with particulate matter in order to seed clouds, artificial carbon sequestration technology to actively remove the carbon dioxide from the atmosphere at a rate faster than natural sinks such as photosynthesis and ocean carbonates, and constructing sun screens in orbit. The pessimistic perspective is that these measures carry additional risks as we've already severely damaged the environment accidentally because we didn't understand it well enough, and any more messing about is liable to make things far worse and far sooner. If that becomes the case, we may have little choice but to attempt more extraordinary measures (i.e. rapid colonization of space[33]).

“”If [discussing renewable energy with conservatives] you deliver the message of energy freedom, energy choice, competition, national security, innovation, all of a sudden, you will have a receptive audience and they will listen to you. If you lead off with climate change, they’re not going to pay a bit of attention to anything else you say. They’ve been brainwashed for decades into believing, oh, we’re not damaging the environment…[34]

As you can see above, fact-based debate on this is as one-sided as bringing an 8-inch atomic artillery piece to a knife fight. So climate denial inevitably involves a barrage of bad-faith misdirection tactics that do nothing to rebut the scientific consensus at issue.

Global warming is happening, it is caused by humanity, it is a bad thing, but even if China and India do something it’s too late for us to do anything and it would cost us a shitload of dough — so we don’t have to change anything.

Global warming was happening, it was caused by humanity, it is a very bad thing and previous governments could and should have done something, but it's too late now![43]

When debating global warming, it is wise to establish beforehand which of the opinions each debater holds, referring to the list above — otherwise you can waste a lot of time proving the wrong point. It may be similar to arguing with someone about the New World Order (NWO) as you need to find out exactly where they stand before engaging with them.

Global warming skeptics have raised a number of slightly more scientific arguments which are covered below.

Many of these claims are thrown into one big denialist soup. However, the problem is that many of them are also contradictory in nature.

For example, the common talking points about it being warmer during the Medieval Warm Period and low climate sensitivity (i.e. "climate is much more stable than that") contradict each other, because the existence of a Medieval Warm Period necessitates high climate sensitivity.

Steve McIntyre deduced, and NASA recently admitted, that NASA programmers had a Y2K bug in their source code that processes temperature data. This bug introduced a 0.02% change in the temperature data that has been corrected. Before this correction 1998 was listed as the hottest year recorded, but this difference was statistically non-significant with the second place year 1934; with the correction 1934 becomes the hottest year. 1934 was a period of intense drought in the United States, as it was during the Dust Bowl years in the Great Depression. The change does not affect the global temperature; it only changes the temperature data for the United States. This confuses global warming deniers, who largely do not understand that the world extends beyond the borders of the United States.

Scientists have found DNA from ancient animals in an ice layer of Greenland, 1.9 km (1.2 miles) beneath the surface.[45] Since this study indicates that the ice layer survived the last interglacial, it has led to speculation that the ice caps may be able to also withstand global warming.[46] However, the main author of the study "dismissed" suggestions that his team's data indicated that sea levels would not rise to predicated levels, saying that "during the last interglacial, sea levels rose by 5-6m, but this must have come from other sources additional to the Greenland ice cap, such as Antarctic ice. I would anticipate that as the Earth warms from man-made climate change, these sources would still contribute to a rise in sea levels."[47]

Another scientist pointed out that it may not be reasonable to extrapolate the study's results to our current situation, because the temperature changes in previous interglacials occurred at a much slower pace.[46] Coincidentally, this article provides more evidence that the world is at least 120,000 years old, which flies in the face of creationists who claim the earth is 6000 years old.

While it is true that natural sources of CO2 release represent a much higher percentage of CO2 output, natural carbon "sinks" that take up that CO2 balance it out. The amount of CO2 in the atmosphere has been relatively constant for hundreds of thousands of years due to output and input being equal. What humans are doing is burning and releasing natural carbon sinks, therefore releasing CO2, without creating additional carbon sinks. This means the net amount of CO2 is increasing over time due to our involvement even though our total output is less than natural sources.

One of the interesting things is that the natural outputs of CO2 and the human-made outputs contain different isotopes. Fossil fuel burning outputs CO2 that has less 14C and 13C than do natural sources. Using tree ring dating it can be shown that the proportion of 14C-containing CO2 in the atmosphere decreased substantially prior to the 1940s, when the largely defensive weapon ofatomic bomb actually negated our ability to use that test. But 13C testing confirmed the 14C testing and showed that fossil fuel burning is the number-one contributor to the increase in the CO2 in the atmosphere.[48]

Volcanic activity, specifically underwater volcanic activity, is often cited (usually drawing on the writings of Ian Plimer) as producing more CO2 than humans. This, however, is demonstrably false.[49] So-called large igneous provinces, mostly lava flows of huge volume (millions of cubic kilometers) that erupt over a few million years, may be associated with rapid global warming, but none have erupted in the past five million years. Within human history, volcanic eruptions tend to have a cooling effect due to emission of sulfur aerosols.

Oddly enough, some denialists also point out the significant amounts of CO2 created by livestock, and somehow totally ignore that these animals are bred and kept by humans, ergo making it human-made emissions. Clearly it is (anthropogenic) burning of fossil fuels that is responsible.

A more bizarre claim was made by Tom DeWeese of the American Policy Center, namely that trees give off CO2 instead of absorbing it. He also claimed that environmentalism was the work of Communist leaders bent on destroying the freedoms of the West after the collapse of the Soviet Union, which indicates that live audio and Dunning-Kruger often go hand in hand.[50] Scientific studies prove Global Warming can not be caused by natural forces alone.[51]

Even if it was not the cause of humans that is causing global warming, this is absolutely not a reason to not do something about it. It would be just as dumb of a decision as it would be to not evacuate people for an incoming earthquake, hurricane, typhoon or volcano eruption simply because humans do not make them happen.

There have been several major changes in the Earth's climate over its 4.5-billion year history. These have included spectacular effects such as the snowball earth and periods of intense global warming. These periods of warming and cooling all have a range of causes mostly involving positive feedback loops, such as ice reflecting the sun back to space causing more ice, reflecting more sun, and Milankovitch cycles, variations in Earth's orbit that have an effect on climate. The warming had similar positive feedback loops, which initially could have been caused by one of many factors but eventually the warming increased the levels of CO2 which then caused even more warming. The fact that CO2 level increases have not been responsible for the start of 100 percent of all global warming events on the planet does not negate the fact that CO2 in the atmosphere does cause warming. Indeed, given that CO2does not lag the current warming is one more piece of evidence demonstrating that established natural cycles are not the cause of the warming.

Water vapour is one of the most potent greenhouse gases in the Earth's atmosphere and accounts for a substantial portion of the greenhouse effect that raises the Earth's temperature from an inhospitable 19 degrees below zero to a more temperate 16 degrees above zero. Global warming denialists have used this to claim that carbon dioxide (CO2) is an unimportant gas in the greenhouse effect — and this can be coupled with the fact that burning fossil fuels (oxidation) results in the release of water vapour in addition to carbon dioxide.

However, this argument that CO2 is not the cause of global warming misses (possibly intentionally) several key facts. First, water vapour is often saturated in the atmosphere. At high altitudes, where the temperature is low, water vapour cools and condenses to form clouds, and if the water droplets are big enough, this leads to rain. The amount of water vapour, therefore, is largely dependent on the temperature.[52] Adding water to the atmosphere may alter weather patterns but its concentration does not differ on the scales considered by climate scientists. As it is removed from the atmosphere on a fast time scale, it can cause short lived but extreme changes in temperature, and so is the cause of much freak, but short-term, weather. Carbon dioxide on the other hand has a much longer life-time in the atmosphere and its concentration is not capped by saturation in the atmosphere. This makes the effect that CO2 has on the Earth's climate a considerable force.[53]

While it is true that there have been cyclical patterns of temperature changes throughout our planet's history, this does not mean that causes are unknown, unknowable, or all the same.[citation needed] The application of the scientific method is great for working out cause/effect relationships. Scientists have managed to link several warming and cooling cycles in the geologic history to specific causes.[54] They have also shown that the modern warming is due to the added output of humans burning fossil fuels and destroying carbon sinks.[55] Past natural climatic patterns that were destructive were associated with cool periods while the projected future catastrophe from AGW is going to be associated with warming; this makes man-made climate change much worse than naturally occurring climate change.[56]

The existence of previous warming cycles does not negate the seriousness of the current one. These previous cycles destroyed a great deal of life on the planet, and if similar effects occurred today they would probably destroy all of human civilization, along with the humanity that created it. This does mean that the earth itself will survive, but that no denialist would be around to gloat.

Changes in the Sun have not been responsible for recent climatic trends; there has not been any significant change in the total energy output of the sun since we have started measuring it, and no changes in the sun or sun phenomenon correlate with increased temperatures.[57] One thing that can change is small perturbations in the orbit of the Earth that draw the planet closer or further from the sun. These perturbations might be linked to the start of several of the major climate changes in the geologic history of the Earth. Nonetheless, the actual change in temperature due to these orbital changes is small and the large scale changes are due to feedback loops localized to Earth pushing things in one direction or another.

There is no evidence that such an orbital shift is happening now, but even if it has, it can only explain a very small percentage of the increase in global temperature. This issue was also a point of contention in the Soon and Baliunas controversy.

Many of the planets and moons (and a certain dwarf planet) in our solar system are big enough and geologically active enough to have both an atmosphere and a climate. In any given system there will be some planets increasing in temperature and some decreasing in temperature. This is due to changes in the localized climate, just as it is with Earth. The causes are different for each planet and have little to no bearing on each other.

Even if the sun does have a role, it is not likely that our own activities are helping the situation. It would actually be even more incentive to temper our works, because anthropogenic activity combined with solar activity obviously equals even higher rates of warming.

This point contends that weather station readings are affected by their proximity to cities, or "urban heat islands." See the article on Patrick Michaels, a notable proponent of this argument, for a treatment of this point.

Denialists love to cherry pick every slight raise to make it seem that Arctic sea ice has stopped melting.

One of the most popular claims made against climate science is that there has been "no global warming since 1998," or even that there has been a pattern of "global cooling" since that year. Denialists who have made this argument include Tim Ball, Nigel Lawson, Fred Singer, Andrew Bolt and Christopher Monckton. The origins of this argument are unclear; perhaps it might have originated in a column by Bob Carter which appeared the Daily Telegraph in 2006.[58]

This argument fails for several reasons: it only takes into account the satellite measurements (UAH and RSS), which doesn't measure directly the surface temperatures. Not only are these satellites run by known deniers John Christy and Roy Spencer, but they are funded in part by Exxon. No conflict of interest there! By contrast, both scientifically accepted surface temperature datasets (GISS and HATCET4) are only funded by government sources, and they show that the warming not only continues, but is accelerating in lock and step with the CO2 emissions. Most importantly, this is one of the finest examples of cherry picking since deniers only look at the data sets that match the conclusions they want to see. Classic climate denialism demands that average global temperature measurements must be taken from the peak of the hottest year and measured to the point trough of the coolest year. If the denialists ever picked years either side of 1998 as their start point, the argument would sink faster than the Titanic. This is because globally, 1998 was a record breaking hot year due to a very strong El Nino.[59] Additionally, another strong El Nino in 2015-16 caused temperatures to soar far past those seen in 1998,[60] so they now have to ignore that time has been passing since 2014 as even their beloved RSS shows a record hot year.

Using arguments such as "Wow, it's really cold today! Global warming, my ass!" or "See! It's snowing in Atlanta for the first time in years!" to argue that "global warming" misuses numerical data, since even without global warming, there are fluctuations in local temperatures. Global warming refers to an overall average increase in temperatures of air and water. Additionally, global warming will temporarily result in some local areas that are cooler, despite the global average increasing.

Strangely enough, this is a common argument used by Fox News and other right-wing organizations who often claim scientists are only using anecdotes of hot weather as proof of global warming when the exact opposite is true. Even more strange, when someone asks where the global warming is because it's snowing where they live, and someone else responds back with "It's 75°F and sunny here, and I'm north of you and up in the mountains" there is often a lingering silence. Apparently anecdotal evidence isn't allowed to work both ways.

Global warming denialists often try to claim that there is no scientific consensus, despite the fact that the IPCC — the main international body associated with investigating the phenomenon — says:[61]

“”Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level... There is very high confidence that the net effect of human activities since 1750 has been one of warming.

Despite this assertion, denialists have attempted to use such methods as the discredited Oregon Petition in an effort to prove their case.

A 2004 study by Naomi Oreskes reviewed over 900 peer-reviewed papers and found none that dissented from the consensus.[62] Criticism of the study has been withdrawn but continues to be repeated in denialist circles.[63] For instance, Lawrence Solomon has claimed that Bennie Peiser, the British scientist who made the criticism, never actually withdrew it and Wikipedia is "censoring" him.[64]

Many deniers will point to record setting Antarctic sea ice as proof that the warming has stopped, but they get quite uncomfortable when you point out the fact that Arctic sea ice and total global sea are at record lows, and continue to decrease at alarming rates. In fact, there is a scientific explanation for the record Antarctic sea ice. As ice on the land melts, it flows into the ocean, reducing the salinity of the ocean, and in turn raising the freezing point of the water.

It is precisely because of the fact that Antarctica is melting that sea ice is growing, and scientists have been predicting this all along, not only because of the melting on land, but also because AGW causes the wind to increase, blowing more snow into the ocean, and further creating a snowfall effect, but reducing the salinity further. [65] Scientists say that this effect is only temporary, and that when the snow on land is reduced by wind and melt to a certain tipping point, the melting of the sea ice will accelerate, which it has done since Antarctic sea ice is now at record lows. [66]

Scientists noticed that historically, the world had been heading towards an ice age.[67] A minority of scientists in the 1970s and earlier also predicted that the pollution would have cooling effect due to increased cloud cover from factories and other emissions. This actually is a thing and does throw a bit of a curveball into the models and appropriate course of action. For example, after 9/11 global air traffic more or less shut down, and the lack of contrails led to the discovery that airplane contrails act to stabilize air temperature throughout the day[68]. The real world is complicated,[citation NOT needed] and people use science to discover how it works. As such, scientific knowledge marches ever forward, and obviously the world has been warming. But the few works published have been enough for "climate skeptics" to strip mine for quotes.

Trotting out the global cooling trope is sometimes called the ice age fallacy.

Climategate was a manufactroversy in which documents were leaked that seemed to indicate a conspiracy to promote global warming among climate scientists... if you didn't understand the language of climate science.

In addition to snarling falsehoods, global warming deniers also like to deride their opponents. While there's nothing wrong with shit-slinging, two terms used by global warming deniers are used in order to imply falsehoods or alarmism.

It's not clear just when or how the denialists adopted CAGW over from the acronym AGW (anthropogenic global warming) used by normal folk. The term was used in blog comments at the New York Times[71] and ScienceBlogs as early as 2008,[72] and is likely to have been used earlier. By around 2011 CAGW had become commonplace in denialist blogs such as those of Anthony Watts or Judith Curry, and over the next year or two essentially replaced AGW in such esteemed venues. Despite the qualifier, denialists apply the term indiscriminately to anything approximating the mainstream scientific view on climate, regardless of whether or not "catastrophic" outcomes are implied.

As for motivation, it's an attempt to move the goalposts. Denialists realized they had lost the argument over plain old "anthropogenic global warming" — the basic physics of the problem have been known since the 19th century,[73] so that rejecting AGW outright paints oneself as a loon. Adding "catastrophic" gives plenty of wiggle room for denialism.[74]Sea level rises a foot? Just a few Pacific Islanders losing everything; no catastrophe. Sea level rises a few more feet? The Philippines get flooded out and we lose coastal cities like London and New York. But with a few trillion dollars we can move them inland; no catastrophe. And so on.

Originally, before the consensus developed, the term was value-neutral. Those who argued for global warming theory were nicknamed "warmists" and those against were called "coolists" or "coldists."[76] Post-consensus, the term warmism is now used in a derogatory sense, often as in "the warmist cult," "the religion of warmism," or "the warmistas." Al Gore is often considered the high priest of the warmist cult.[77] The term "coolist" has mostly fallen out of use, being largely replaced by "skeptic" (for journalists who want to seem balanced) or "denier." The "warmist" versus "denier" terminology is akin to "evilutionist" or Darwinist versus creationist in the debate over evolution, except the former pair tends to be used with more seriousness than the latter.

A third but smaller breed has positioned itself between the "warmist/denier" dichotomy — the "lukewarmer." Unlike the other two labels, however, "lukewarmer" is often used as an un-ironic self-descriptive term. Lukewarmers tend to eschew outright denying climate science in favor of systematically low-balling IPCC estimates (see also Bjorn Lomborg).[78]

“”The danger of global warming is as yet unseen, but real enough for us to make changes and sacrifices, so that we do not live at the expense of future generations. Our ability to come together to stop or limit damage to the world's environment will be perhaps the greatest test of how far we can act as a world community. No one should underestimate the imagination that will be required, nor the scientific effort, nor the unprecedented co-operation we shall have to show. We shall need statesmanship of a rare order.

A rise in sea level: The most conservative prediction of sea level rise presently predicted is 9–88 cm (3.5–34.6 inches). This small rise would be enough cause significant disruption to coastal communities.[79]

There is a possibility, however, that the whole Greenland ice sheet would melt leading to a global rise of 7 m (23 ft). There is even a possibility that the West Antarctic ice sheet could melt raising sea levels by a further six meters (20 feet). Although the rest of the Antarctic is considered to be stable, if the entire Antarctic were to melt, this would raise sea levels by 62 meters (203 feet).[81] Although this isn't enough to turn the Earth into Waterworld, it's more than enough of a rise to render every major coastal city on the planet uninhabitable. Want a visualization? Say goodbye to Miami, NYC, New Orleans, Venice, Tokyo, Mumbai, and Shanghai.[82]

In addition to the rises in sea level caused by melting glaciers, sea level would also rise as a consequence of the thermal expansion of the warmer water.

More active weather systems: More energy in the atmosphere will lead to more active weather systems, with more frequent and more violent storms. More severe weather events such as storms, floods, heatwaves and hurricanes will be the result.[83] Hurricanes will become more severe and long-lived as the Earth warms, specifically due to the warming of the oceans. It is warm sea surface temperatures above 26 °C that are required for hurricanes to form, and to be able to sustain themselves because the heat that fuels hurricanes is from the latent heat of condensation.

Disturbed rainfall patterns: Rainfall patterns will be significantly disrupted with floods in some places and droughts in others. Regions closest to the equator (central Africa, Latin America, India, Southeast Asia, etc.) are more likely to face extreme vulnerability.[84]

Acidification of the oceans: The ocean has a limited capacity to dissolve carbon dioxide before it ceases to absorb any more thus leading to further warming. This would also cause great damage to fish stocks. The acidity (pH) of the ocean is currently ~8.0, slightly alkaline, and the earliest signs of increasing acidity (and temperature) is coral bleaching, where the photosynthetic mutualists in the coral die leading to the collapse of the coral reefs which are often described as the 'rainforests of the sea' due to the level of biodiversity.

Tipping points/feedback loops: There are many possible tipping points and feedback loops. For instance, if global warming causes the northern permafrost to melt this will release vast amounts of methane which will make the problem much worse. It is thought that a similar release of frozen methane hydrate from arctic ocean floors resulted in a runaway greenhouse effect at the end of the Permian period, which may have been a leading cause of the Permian mass extinction.

Spread of tropical diseases: As northern latitudes become warmer previously-rare tropical diseases will gain a foothold in more northern latitudes.[85] The World Health Organization has identified more than 30 new or resurgent diseases in the last three decades, the sort of explosion some experts say has not happened since the Industrial Revolution brought masses of people together in cities. Another report made by WHO in 2000 found that warming had caused malaria to spread from three districts in western Kenya to 13 and led to epidemics of the disease in Rwanda and Tanzania.[86] However, the relationship may not always be so simple — one study demonstrated that warmer temperatures may increase the number of malarial parasites but also decrease the rate at which they become infectious.[87] In Sweden, cases of tick-borne encephalitis have risen in direct correlation to warmer winters. Asian tiger mosquitoes, the type that carry dengue fever, have been reported recently as far north as the Netherlands. Cholera, which thrives in warmer water, appeared in the newly warmed waters of South America in 1991 for the first time in the 20th century. "It swept from Peru across the continent and into Mexico, killing more than 10,000 people." Once confined to land near the equator, West Nile Virus is now found as far north as Canada. Seven years ago, West Nile virus had never been seen in North America; today, it has "infected more than 21,000 people in the United States and Canada and killed more than 800."[88]

Cold weather no longer kills ticks that carry Lyme disease. Ticks recently began spreading along the coastlines of Scandinavia, which formerly was too cold for them to survive. Cases of Lyme disease in the area have doubled since the late 1990s.[89]

Disruption of ocean currents: The disruption of ocean currents could shut down the Gulf Stream with unpredictable consequences. Melting of the ice sheets could result in a weakening of the thermohaline circulation as the Arctic and Antarctic Ocean's warm, decreasing the temperature difference and thus flow of heat as it's redistributed from the equatorial regions to the high latitudes. It is believed that the collapse of the ocean currents may lead to extreme levels of ocean anoxia, because the currents are essential for carrying dissolved oxygen below 500 meters of depth. This may possibly mean wiping out the overwhelming majority of multi-celluar ocean life.

Habitat loss/change faster than animals can adapt: Temperature zones will move north and south too quickly for animals to follow or adapt to new habitats. The most extreme case is that of arctic habitats which will leave animals such as polar bears with no place to go. In 2007 Indonesia's environment minister has announced that scientific studies estimate about 2,000 of the country's lush tropical islands could disappear by 2030.[90] Deserts have already started increase in size toward higher latitudes, and are projected to increase in size by 10%-30% by the end of the 21st century.[91]

Climate exodus: Okay right-wing, you can deny immigration or deny the existence of climate change but you can't deny both. One major issue is the massive flood of migrants that will happen in coming decades as a result of increasing uninhabitability. It will likely spread like a wave, first affecting nations near the equator and slowly moving further away. It will start with poorer countries in the region, but eventually, wealthier countries in the region will collapse due to either the migrant crisis or temperatures getting too hot for technology to balance it out anymore. As the crisis spreads, extremism will explode as opinions on what to do contradict each other. Some major powers may go crazy and begin performing border massacres and invasions, in an attempt to stop the wave of migrants and impending economic collapse as a result of the collapse of cheap labor and the potential rise of autarky. Internal migration will likely become an issue in some nations as parts such as the American Southwest begin to lose inhabitability to desertification. Hopefully, it'll stop around this point, but it may keep going as a trend moves humanity further and further from the equator. Extremist militias would likely dominate the depopulated former nations. At this rate, the trend will likely start with Southeast Asia and central Africa.

Loss of mountain glaciers: Mountain glaciers act as natural reservoirs, releasing winter snow as meltwater during the summer. Global warming will disrupt this system in two ways:

More rain will fall instead of snow which will prevent the reformation of the glaciers. The result of this will be more floods when it rains and droughts when it does not.[93]

Hans Island as seen from the air

Social effects: Global warming and the retreat of Arctic ice is already causing social repercussions for various nations. A good example of this is the battle for control of Hans Island. Hans Island is a barren, uninhabited chunk of rock fully two square kilometres in surface area that is bisected by the dividing line between the respective territories of Greenland and Canada.[94] In the past the sovereignty of this insignificant island was undisputed since it was economically worthless, but with summer pack ice ever retreating it may shortly be the case that control of Hans Island grants access to huge, untapped hydrocarbon deposits as well as control of shipping through the Nares Strait.

There has been considerable diplomatic tension between Canada and Denmark (who represent the interests of Greenland in all international affairs) over the sovereignty of the island. Both nations have made expeditions to the island to plant their respective flags, and assert their claim to the island. Like all good controversial issues, the battle for Hans Island has spawned a large number of parody sites on the Internet.[95][96]

Agricultural effects: Drought could have major influence on agriculture[97] as could flooding or massive change in temperature. This could have major economic impact in developed countries and threaten food supplies in poor nations. Effects on agriculture can be positive or negative but overall outcomes of agricultural activity become less predictable.[98]

Not all of these consequences are certain, and some may be mitigated. For example, whilst global warming might tend to promote the spread of tropical diseases, advances in medicine or control measures (insect spraying, swamp draining) could well counteract this, as has already happened during the industrial era for a number of previously common diseases.

If climate change doesn't sound so bad, consider that we've spent the past few hundred years building cities in places that don't flood, farms in places with enough water, and ice hotels in places with, well, ice. There is an awful lot of money and human endeavor relying on the weather staying just the way it is.

It has been hypothesized that the added heat and CO2 from global warming would increase plant growth, thus creating a "greener" Earth. However, a 17-year experiment on California flowers and grasslands found that plants growing with extra heat or CO2 did not grow more, did not remove pollution and did not store more of it in the soil. Only extra nitrogen made plants greener.[103] It has also been found that the increased plant growth will not likely be sustained, and that the increased CO2 also causes decreases in some important nutrients, such as selenium and zinc.[104]

It should also be noted that global average temperatures were higher during the Jurassic period than they are today. This does not, unfortunately, mean that global warming will bring back the extinct dinosaurs. The currently living ones such as chickens, on the other hand, may evolve to fill the new niches. So if you want a world where your puny children are mere morsels for the almighty Cockasaurus Rex, trade in that SUV for a hummer.

There are some positive impacts that deniers like to use such as longer growing seasons in Canada and northern Europe, but they never bring up the fact that even really bad things have some positives. What's important is not really if there are any positives, but rather, if the positives outweigh the negatives. When economists, scientists, and engineers perform cost-benefit analysis of global warming, the negatives outweigh the positives 25 to 1. When you bring this fact up with deniers, they quickly change the subject. [105]

The "global warming wager" is an application of the precautionary principle to the anthropogenic theory of global warming (some have drawn parallels are drawn with Pascal's wager[106]). That is, even if there is uncertainty that global warming is happening, we have to prepare for the worst case scenario anyway:

“”Businessweek columnists Jack & Suzy Welch say they believe that, whether the impact of global warming ends up being mild or severe, companies have to adopt a 'here it comes' mind-set and mount a well-reasoned plan. Any other response would be bad business.[107]

This argument is unlikely to advance a conversation as Pascal's wager has several known logical issues that render it useless as a decision making tool in the face of uncertainty. However, in this case, the impact of human-generated pollution on the Earth's temperature has been and is being directly observed. Arguments against the likelihood of negative consequences can be met directly with evidence.

“”Plot idea: 97% of the world's scientists contrive an environmental crisis, but are exposed by a plucky band of billionaires & oil companies.

—Scott Westerfeld

The "Global Warming Conspiracy Theory" (GWCT) refers to the questionable ideas bandied about by global warming denialists that global warming either isn't happening or is being over-hyped by a group of people who feel that they have some advantage to gain by promoting the evidence for global warming, apparently never having considered how much Oil Companies gain from denying the evidence for Global Warming.

Besides the general nonsensical nature of many of these theories, they generally fail to answer how the conspiracy reaches back to John Tyndall's discovery of the greenhouse effect in 1859 (perhaps Al Gore invented a time machine after he was done with the Internet).[108]

“”So-called global warming is just a secret ploy by wacko tree-huggers to make America energy-independent, clean our air and water, improve fuel-efficiency of our vehicles, kick-start 21st century industries, and make our cities safer and more livable. Don’t let them get away with it!

As is typical of many conspiracy theories, there is not one theory but several contradictory ones. Some of the ones identified here are now a little out of date, and no doubt conspiracy theorists have now invented some other tortured reasons for people backing the "conspiracy." Because of the multiplicity of contradictory theories, it is a good idea to get a global warming denialist to explicitly state which particular "theory" they are backing.

A genealogy of climate change conspiracy theories can be found at the International Journal of Inactivism.[110]

The following are some of the many specific conspiracies identified regarding global warming. Note that this lists conspiracies rather than flat-out denials, though they often go in tandem.

NWO scheme: It's an attempt by scientists, politicians and environmentalists to take over the world. According to William M. Gray, they wish to find "a political cause that would enable them to organize, propagandize, force conformity and exercise political influence.'" Apparently Al Gore has something to do with it.[115] Muahahaha!

Climate science funding scheme: It's all a hoax invented by all the world's climate scientists to get funding.[117] The "evil" scientists have managed to fool the UN, the European Union, and the entire world.[118] This angle is also rather ironic considering that a sinecure at a denialist think tank can easily pay better than an actual post as a climatology professor.

Anti-Africa scheme: It's a plot by those nasty environmentalists who want to prevent Africa developing a carbon economy. Alternatively, it's a plot by environmentalists who want to promote a carbon economy in Africa while damaging the USA's industrial output.[120] Two "theories" for the price of one!

Anti-globalist scheme: This one suggests that it's associated with the anti-globalisation movement and it's an attempt to cripple the world economy.[121] But how one can accept international treaties while opposing globalization is never explained.

Pro-nuclear scheme: According to this "theory," it's all about an attempt by Margaret Thatcher, and presumably her successors, to make the people of the world accept non-CO2-producing nuclear power.[122] It's not exactly clear what Phase 2 is, but Phase 3 seems to be "profit." This was promoted in the film The Great Global Warming Swindle. As it becomes clear that "politically correct" renewable energy sources such as wind and ground-based solar are unable to meet the needs of civilisation, expect this one to be uttered more often by fossil fuel industry opponents. It is noteworthy that the UK nuclear power industry has been handed over to the French! (see Jacques Chirac above)

Socialist scheme: This theory claims that a carbon emissions tax (as proposed again by Al Gore, OMG!) would allow the United States government to gain substantial influence over industry (which, after the way they've managed to facilitate a global recession, wouldn't be a bad thing, if the recession wasn't mostly caused by problems in the housing market, of course).[123] Exactly why Al Gore would benefit from the US government controlling corporations is unclear. Furthermore, with all the investment the government is presently being forced to make in industry, it may end up controlling a lot of it whether it has a carbon tax or not.

Eugenics and/or depopulation scheme: This brand of the conspiracy theory states that global warming is a front for the implementation of a worldwide eugenics program or a scheme to depopulate the planet and kill off the "useless eaters."[126][127] Quotes from nutty hard greens (Pentti Linkola is a perennial favorite) often come in handy for "proving" this. A particularly amusing if little-known variant of this conspiracy theory posits that the depopulation plan was initiated by the anthropologist Margaret Mead at a 1975 conference on overpopulation.[128] This theory is more popular in the conspiracist pro-life circles due to its connection with the issue of abortion and it also makes for some good red-baiting material due to China's one-child policy, and you don't want to end up like those dirty Reds now do you?

Fake news scheme: This scheme most notably surfaced with Rush Limbaugh and Alex Jones casting doubt on forecasts of extreme weather events, in particular Hurricane Irma of 2017.[129][130] Limbaugh's gambit is that the media benefits from increased advertising revenue from people watching extreme weather events on TV and retailers benefit from increased sales from extreme weather preparation, therefore it's fake news and part of the the climate-change conspiracy.[129]

There are many entrenched interests who benefit from the current energy infrastructure of our modern civilization. Commonly mentioned "villains" are oil companies (as well as the complicit politicians they lobby) who would stand to lose a lot of money if action were taken to reduce the amount of carbon dioxide dumped into the atmosphere, as this would imply a reduction in the use of fossil fuels such as oil. But consumers are "the other half" of the same problem and (for example) US drivers have been very resistant to an increase in petrol taxation.

Exxon (later ExxonMobil) has known since at least 1977 that global warming from fossil fuels could be an issue. By 1981, Exxon was "already factoring climate change into decisions about new fossil fuel extraction". In 1995, there was an internal Exxon report that unequivocally stated that "burning the companies' products was causing climate change and that the relevant science 'is well established and cannot be denied.'"[132][133]

Consequently by way of coverup, corporate interests have spent a vast amount of cash[134][135] in an effort to discredit the science behind man-made global warming, and encourage global warming denialism.[136] ExxonMobil has been one of the prime movers and Greenpeace reports have stated:

“”ExxonMobil's campaign to fund "think tanks" and organizations that spread misinformation about the science and policies of global warming is now widely known. The company’s multimillion dollar campaign has undoubtedly contributed to public confusion and government inaction on global warming over the past decade."[137]

Greenpeace is still monitoring ExxonMobil's attempts to distort public opinion in this area as can be seen in their website exxonsecrets dedicated to exposing the company's activities.

The disinformation campaign is similar to that embarked on by the tobacco companies who wished to persuade people that cigarettes were healthy,[138] and the campaigns carried out by the oil companies when they wished to continue adding lead to petrol. Indeed, the similarity between not only the techniques used by denialists to defend smoking and claiming that acid rain and global warming is either natural/not a huge problem/too expensive to fix, but also the overlap and interconnection in the cast of experts for hire trotted out was the core argument in the book Merchants of Doubt.[139]

Some members of the public get confused between ozone layer depletion and global warming — both involve some gases that somehow influence the already arcane dynamics of the atmosphere, and both are associated with dire consequences if we do not change our comfy lifestyle. There is a slight connection: Both ozone (O3) as well as the ozone killing chlorofluorocarbons (CFCs) act as greenhouse gases, but on a smaller scale than the usual suspects carbon dioxide (CO2) and methane (CH4).[140][141][142]

However, they are largely separate issues: ozone layer depletion means that we all die because the ozone layer vanishes and the surface of Earth is bombarded with ultraviolet solar radiation, and global warming means that we face incredible hardship because the temperatures on earth rise too quickly for the ecosystems to adapt and the entire biosphere collapses.

So, we can do this two ways: suck it up and take the necessary steps now to mitigate the expected damage to human civilization, or wait another few decades debating PRATTs while millions — potentially billions — of people die around us.

↑Correlation of global temperature with solar activity "While it appears that the measured solar cycle length tracks the temperature better than the CO2 concentration for the twentieth century up to 1970, this presented data remains quite controversial. When you look at the climate models that seek to show the human influence past 1970, you do see a good correlation of the temperature with the projected CO2 influence included, while the correlation with solar cycle length weakens."

↑Didn't the UN already collectively take over the world, or most of it already? I mean the member nations spans almost the entire world's land above water. I can understand taking over a country as in interfering the policies of that country, but the world as a whole is mostly controlled by UN as a whole since pretty much after World War II.